技術者から見たあの事故
お盆になると御巣鷹山に墜落した日航機の件を思い出します。このような大きな事故が起こりますと、航空機にかかわる者としては暗い気持ちになります。
そして原因は貴重な教訓として語り継がれています。
日航123便の教訓としては、下記の通りです。(公的に発表された事故報告書を信じた場合の教訓です)

(1)圧力隔壁が疲労で壊れた
昔から、コメット(※最後に説明あり)空中分解以来機体の構造疲労は注目されておりましたが、日航123便以後は特に重視されるようになりました。
現在は必ず機体疲労計算を徹底的に実施し、可能な限り飛行中の荷重を正確に模擬して地上耐久疲労試験にて確認することになっております。34年前と比較すると格段に試験方法が進化しました。
(2)尾翼が破壊されて操縦不能になった
尾翼が破壊されることは、想定外の不具合です。パイロットは主翼のみで飛行するなど想定外でした。訓練すれば主翼についているエルロン、フラップ、スラット、スポイラーをうまく操作すると操縦可能になります。このような訓練などしてなかったわけです。
その後フライトシミュレータによる模擬故障飛行訓練の一つに追加されたと聞いております。
(3)機体が爆発的に燃えた
機体の中で燃えやすいものは、燃料、作動油、座席などです。このとき作動油が昔ながらの燃えやすい作動油ですと、簡単に着火し、たちまち燃え上がるMIL-H-5606作動油を使っていたかどうか、定かではありません。少なくとも、今は改善された燃えにくいスカイドロール油になっています。座席もより不燃に近くなっています。
(4)当時の操縦システムは油圧が多く使われていたが次第に電気系に代わってきた
以上。
その他にもテロ防止安全対策など、より空の旅を安全に楽しめるように進化しております。
(-人-)
520名の犠牲者の方々のご冥福をお祈り申しあげます。
注※コメット…英国の航空機メーカが開発した世界最初のジェット旅客機。1954年ごろ連続空中分解を起こした。初めはテロが疑われたが実験結果、機体構造の金属疲労であったことがわかった。
広告PR: 航空業界を目指すあなたに。

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